[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-113-1-fire-science-032":3},{"subject":4,"subjectSlug":5,"subjectKicker":6,"subjectShort":7,"question":8,"related":27,"sameNumber":52,"hasEssay":26},"火災學概要","fire-science","火災學 · Fire Science","火災學",{"id":9,"webId":10,"year":11,"session":12,"subject":4,"number":13,"stem":14,"options":15,"answer":20,"answerNote":21,"images":22,"imagesPending":23,"lawTimestamp":11,"explanation":24,"explanationDeep":25,"freq":12,"indexable":26},"fire-113-1-火災學概要-032","fire-113-1-fire-science-032",113,1,32,"可燃物在大氣中僅因受熱致使溫度升高而引發燃燒的最低溫度稱為：",{"A":16,"B":17,"C":18,"D":19},"發火點","閃火點","燃燒點","閃燃點","A",null,[],false,"本題考點：發火點的定義，以及它與閃火點、燃燒點三個溫度常數的區別。\n【正解理由】依燃燒學定義，可燃物在空氣中不藉助外部火焰或電氣火花等點火源，僅因受熱使溫度上升即自行起火燃燒的最低溫度，稱為發火點，亦稱著火點或自燃溫度。題幹「僅因受熱致使溫度升高而引發燃燒」正是排除外部點火源的關鍵敘述，故選 A。\n【逐項排除】\n(A) 發火點敘述相符，為應選項；其成立條件即無外部點火源而能自行起火。\n(B) 閃火點指液體表面蒸發的蒸氣與空氣形成可燃混合氣後，遇外部點火源產生瞬間閃燃的最低溫度，火焰無法持續，且必須有點火源，與題幹條件不符。\n(C) 燃燒點指液體遇點火源引燃後，火焰能持續燃燒的最低溫度，通常較同一液體的閃火點高出攝氏數度，同樣需要外部點火源。\n(D) 閃燃點並非物質的溫度常數；閃燃是室內火災由成長期轉為最盛期的瞬間全面延燒現象，屬火災階段的描述而非可燃物的性質。\n【記憶點】不用點火源、自己燒起來的最低溫度是發火點；要靠火源才閃一下的是閃火點。","三個溫度常數的高低次序固定為閃火點小於燃燒點小於發火點，理由可由燃燒要素推得。閃火點只要求液面上方的蒸氣濃度剛好達到燃燒下限，遇火源即可閃一下；燃燒點要求蒸氣的供應速率足以支撐火焰持續存在，故需再高一些的溫度；發火點則連點火源都沒有，必須靠溫度本身讓氧化反應的產熱速率超過散熱速率而失控，所需溫度自然最高，往往高出數百度。\n\n閃火點在我國法規上是公共危險物品分類的核心指標。依《公共危險物品及可燃性高壓氣體製造儲存處理場所設置標準暨安全管理辦法》附表一第四類，易燃液體指一大氣壓時閃火點在攝氏九十三度以下之液體，其中第一石油類為閃火點未達攝氏二十一度者，第二石油類為攝氏二十一度以上未達七十度者，第三石油類為攝氏七十度以上未達二百度者；可燃液體則指一大氣壓時閃火點超過攝氏九十三度未滿攝氏二百五十度之液體。同表第四類第一目的特殊易燃物更同時用到兩個概念，指一大氣壓時自燃溫度在攝氏一百度以下之物品，或閃火點低於攝氏零下二十度且沸點在攝氏四十度以下之物品，可見自燃溫度與閃火點在同一目中並存而各有分工。\n\n易混淆概念對照：發火點是溫度，發火源則是能量來源，兩者名稱相近而意義不同；閃火點依測定方式又分開杯法與閉杯法，閉杯測得值通常較低，做物質比較時測定方法必須一致。同一物質的發火點也會隨測定容器材質、加熱速率與試樣量而略有差異，教科書所列數值多屬代表值而非絕對不變的常數。相關考點延伸：本科常給一組液體的閃火點要求判斷所屬石油類別，或反過來由類別推估閃火點範圍。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-113-1-fire-science-031","在電氣火災研究中，木材、電木等絕緣物中，受電氣火花而碳化，碳化部分會逐漸形成微量的結晶，而變成具有導電性，此現象稱為？",31,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-113-1-fire-science-033","對於金屬鈉的敘述，下列何者錯誤？",33,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-113-1-fire-science-030","有關煙控分析中「等效流動面積」的定義，下列敘述何者正確？",30,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-113-1-fire-science-034","有關熱傳導的敘述，下列何者正確？",34,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-113-1-fire-science-029","火場中的單位長度光學密度為 1 m-1 時，此火場中的發光物體之能見度約為多少公尺？",29,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-113-1-fire-science-035","某鑄造工廠因高溫鋁水洩漏，遇水引發爆炸，此為何種爆炸？",35,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-112-1-fire-science-032",112,"將大塊的木頭切碎為小片的木屑時，下列敘述何者錯誤？",{"webId":58,"year":59,"stem":60,"number":13},"fire-111-1-fire-science-032",111,"下列何者非油槽火災發生沸溢或濺溢的主要因素？",{"webId":62,"year":63,"stem":64,"number":13},"fire-110-1-fire-science-032",110,"有關爆炸性物質之特性，下列何者正確？",{"webId":66,"year":67,"stem":68,"number":13},"fire-109-1-fire-science-032",109,"已知天花板噴流溫度攝氏 135℃，天花板噴流速度 1.8 m\u002Fs，環境初始溫度 20℃，感知撒水頭作動溫度攝氏 72℃，反應時間指數 67(m1\u002F2s1\u002F2)，感知撒水頭作動時間為下列何者？（提示： ln115=4.74, ln63=4.14）",{"webId":70,"year":71,"stem":72,"number":13},"fire-108-1-fire-science-032",108,"下列有關防止靜電災害的方法中，何者錯誤？",1785129966361]